prEN ISO 21012
(Main)Cryogenic vessels - Hoses (ISO/DIS 21012:2021)
Cryogenic vessels - Hoses (ISO/DIS 21012:2021)
Kryo-Behälter - Schlauchleitungen (ISO/DIS 21012:2021)
Récipients cryogéniques - Tuyaux flexibles (ISO/DIS 21012:2021)
Kriogene posode - Gibke cevi (ISO/DIS 21012:2021)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 21012:2021
01-november-2021
Kriogene posode - Gibke cevi (ISO/DIS 21012:2021)
Cryogenic vessels - Hoses (ISO/DIS 21012:2021)
Kryo-Behälter - Schlauchleitungen (ISO/DIS 21012:2021)
Récipients cryogéniques - Tuyaux flexibles (ISO/DIS 21012:2021)
Ta slovenski standard je istoveten z: prEN ISO 21012
ICS:
23.020.40 Proti mrazu odporne posode Cryogenic vessels
(kriogenske posode)
83.140.40 Gumene cevi Hoses
oSIST prEN ISO 21012:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 21012:2021
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oSIST prEN ISO 21012:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21012
ISO/TC 220 Secretariat: AFNOR
Voting begins on: Voting terminates on:
2021-09-17 2021-12-10
Cryogenic vessels — Hoses
Récipients cryogéniques — Tuyaux flexibles
ICS: 83.140.40; 23.020.40
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 21012:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2021 – All rights reserved
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Design and construction . 2
4.2 Materials . 3
4.3 Cleanliness . 3
4.4 Mechanical properties . 4
4.4.1 Burst pressure . 4
4.4.2 Pressure cycles . 4
4.4.3 Bending test (optional, upon request of purchaser) . 4
4.4.4 Resistance to abuse . 4
4.4.5 Low temperature resistance . 4
4.4.6 Leak tightness. 4
4.4.7 Electrical properties . 4
5 Hose sample tests . 4
5.1 General . 4
5.2 Non-destructive tests and inspection . 6
5.2.1 Documentation of materials . 6
5.2.2 Dimensional check . 6
5.2.3 Cleanliness check . . . 6
5.2.4 Pressure test . 6
5.2.5 Leak test . 6
5.2.6 Crushing test. 6
5.3 Destructive tests . 7
5.3.1 Hydraulic pressure cycling . 7
5.3.2 Rolling bend cycling test . 7
5.3.3 Hydraulic bursting test . 7
5.3.4 Examination of sectional cut . 8
6 Production testing . 8
6.1 General . 8
6.2 Pressure test . 8
6.3 Leak test . 8
7 Marking . 8
8 Cleaning . 8
9 Periodic examination . 9
10 Test certificate . 9
Annex A (informative) Typical hose assembly .10
Annex B (informative) Rolling bend cycling test for metallic hose assemblies and hose
assemblies made of materials with a record of satisfactory use in cryogenic service .11
Annex C (informative) Rolling bend cycling test for hose assemblies constructed from
materials or composites not commonly used in cryogenic service .13
Annex D (informative) Guidelines for periodic examination of transfilling hoses .15
Annex E (informative) Acceptable materials .16
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/68/EU (Pressure Equipment Directive) aimed to
be covered . .21
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by ISO/TC 220, Cryogenic vessels, in collaboration with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 268, Cryogenic vessels, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 21012:2021), which has been technically
revised.
This edition includes the following significant changes with respect to the previous edition:
— Modification of the scope
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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oSIST prEN ISO 21012:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 21012:2021(E)
Cryogenic vessels — Hoses
1 Scope
This document specifies design, construction, type and production testing, and marking requirements
for non-insulated cryogenic flexible hoses used for the transfer of cryogenic fluids within the following
range of operating conditions:
— working temperature: from −270 °C to +65 °C;
— nominal size (DN): from 10 to 100.
End fittings for mounting of any couplings are within the scope of this document, but the couplings are
subject to other standards.
It is intended that the hose be designed and tested to satisfy a rated pressure. Hoses may be then
selected with a PR equal to or greater than the maximum allowable pressure (PS) of the equipment to
which it is to be used.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 7369:2020, Pipework — Metal hoses and hose assemblies — Vocabulary
EN ISO 10806:2003, Pipework — Fittings for corrugated metal hoses
ISO 21010:2017, Cryogenic vessels — Gas/material compatibility
EN ISO 21028-1:2016, Cryogenic vessels — Toughness requirements for materials at cryogenic
temperature — Part 1: Temperatures below −80 °C
EN ISO 23208:2019, Cryogenic vessels — Cleanliness for cryogenic service
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN ISO 7369:2020 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
hose
flexible leak-tight inner tube of either corrugated metal, elastomer or plastic
3.2
braid
layer, or layers, of cylindrically woven wires covering the hose and permanently attached to the flexible
hose assembly end fittings, serving the function of restraining the flexible hose against elongation
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
3.3
protection coil or cover
outer coil or cover fitted to protect the main hose and braid against damage and abrasion
3.4
end fittings
fitting (of material compatible with material and product transferred) attached to each end of the hose
and braid (when fitted)
3.5
hose assembly
hose with end fittings attached, complete with braid and/or other covering, ready for service
3.6
nominal size
DN
alphanumeric designation of size for components of a pipework system, is used for reference purposes
Note 1 to entry: It comprises the letters DN followed by a dimensionless whole number that is indirectly related
to the physical size, in millimetres, of the bore or outside diameter of the end connections.
[SOURCE: ISO 6708:1995, 2.1]
3.7
rated pressure
PR
lowest maximum allowable working pressure (MAWP) of any component of the hose at
20 °C
Note 1 to entry: PR > PS (as defined in PED).
Note 2 to entry: See also the last sentence of Clause 1.
3.8
rated minimum temperature
lowest temperature to which the hose assembly is rated by the manufacturer
3.9
working temperature range
highest and lowest temperature to which the hose assembly is to be subjected
3.10
cyclic life
minimum number of complete cycles which, at the test conditions, the hose assembly is designed to
withstand without failure
4 General requirements
4.1 Design and construction
The test pressure used during tests (see Clause 5) shall be greater than or equal to the rated pressure
(PR) specified. In addition, the rated pressure (PR) shall not be less than the maximum allowable
pressure (PS) of the equipment to which it is to be used. A hose is typically made from corrugated
metal, from strip steel. The corrugation may be parallel or helical. The maximum pressure in service
shall be lower than or equal to the rated pressure stamped on the hose assembly.
If elastomers or composites are used, additional requirements shall be applied in accordance with
5.3.2.2.
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
A braid is commonly fitted over the hose. This generally consists of woven wire in one or two layers
in stainless steel, or a high strength copper alloy. It may have a cover that shall be compatible with the
surroundings and with the conveyed fluid.
The design shall ensure that pressurization, or corrosion, between the inner tube and the outer braid or
sheath is prevented.
End fittings shall be designed as a rigid seal to the ends of a hose to ensure:
— a tight fit to the hose;
— a strong joint between the braid, hose and end fitting to stabilize the hose against elongation at
rated pressure.
Fittings for corrugated metal hose assemblies shall conform to EN ISO 10806:2003.
An area for marking shall be provided on one of the end fittings or on an attachment.
All joining methods used in corrugated hose assemblies shall be qualified. Manual welds shall be in
accordance with applicable standards.
A typical cryogenic hose assembly is shown in Annex A.
4.2 Materials
All materials shall be compatible with the fluid conveyed and shall be controlled by the manufacturer of
the hose assembly by a specification ensuring control of chemical content and physical properties, and
quality at least equivalent to an internationally recognized standard. Materials for the manufacture of
corrugated metal hose assemblies shall be selected on the basis of their suitability for fabrication, e.g.
cold forming and welding, etc. and for the conditions under which they shall be used. In addition, the
following requirements shall be met:
— end connections and couplings shall be made of materials compatible with the other materials of the
hose assembly;
— a material is compatible when it does not lead to any violent reaction (ignition, etc.) or any slow
reaction with the conveyed gases, and permeability shall be appropriate for intended use;
— a test certificate providing the chemical content and physical property test results shall be provided
with the hose assembly.
The materials used in a cryogenic hose assembly shall:
— maintain sufficient ductility at the rated minimum temperature (as specified in EN ISO 21028-1:2016);
— be oxygen compatible, if specified for oxygen or nitrous oxide service (as specified ISO 21010:2017);
— any austenitic stainless steel hoses shall be annealed after formation for hydrogen service;
— contain less than 65 % copper, in the alloy as well as the soldering materials, if it is specified for
mixtures containing acetylene.
A list of acceptable materials is given in Annex E (Table E.1 for European materials, Table E.2 for non-
European materials).
4.3 Cleanliness
Hose assemblies specified for all cryogenic fluids shall be cleaned in accordance with EN ISO 23208:2019
to remove hydrocarbons, moisture, particles or other contaminations from inside the hose assembly.
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
4.4 Mechanical properties
4.4.1 Burst pressure
The burst pressure shall be at least three times the rated pressure at ambient temperature. Failure
shall occur only in the body of the hose and braid and not in their connections. See 5.3.3 for burst test.
4.4.2 Pressure cycles
Hose assemblies shall have a minimum cyclic life of 10 000 cycles when repeatedly pressurized from <1
bar to their rated pressure in accordance with 5.3.1.
4.4.3 Bending test (optional, upon request of purchaser)
Hose assemblies should have a minimum cyclic life of 10 000 cycles when repeatedly flexed at their
rated pressure in accordance with 5.3.2.
NOTE Actual life cycle of hose will depend on actual operating conditions.
This test is only required if the flexible hose is subject to multiple wide/significant moves when under
pressure.
4.4.4 Resistance to abuse
Hose assemblies should have sufficient resistance to deterioration of the braid when they are dragged
on the ground. For additional protection of the braid, a coil can be used.
Hose assemblies shall withstand a crushing test, simulating a person stepping on the hose assembly, in
accordance with 5.2.6.
4.4.5 Low temperature resistance
All components of the hose assemblies which become cold during operation shall retain their toughness
at the lowest design temperature.
4.4.6 Leak tightness
Hose assemblies shall be leak-tight in accordance with 5.2.5.
4.4.7 Electrical properties
Hose assemblies specified for flammable products shall be electrically conducting from one end to the
other (electric resistance less than 25 Ω).
5 Hose sample tests
5.1 General
The hose test samples shall be representative of production. In case of a connection breaking pre-
programmed system, testing will be performed on flexible hoses without these connections. The hose
sample test procedures shall include:
a) inspection and non-destructive tests:
— inspection: dimensions, cleanliness, material identification and marking;
— tests: pressure test, leak and crushing tests;
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b) destructive tests:
— pressure cycling, bursting test, rolling bend cycling and examination of sectional cut.
The tests shall be recorded in a written report which shall be retained for 10 years after the last hose
has been placed on the market.
Four sample hose assemblies (A, B, C and D) are necessary to perform the tests.
The tests and order of tests are summarized in Table 1.
(The numbers 1 to 5 give the order of the tests).
Table 1 — Testing scope and sequence
Tests Hose sample
A B C D
1) Non-destructive tests
Documentation of materials 1 1 1 1
Dimensional check 1 1 1 1
Cleanliness check 1 1 1 1
Pressure test 1 1 1 1
Leak test 2 4 3 2
Crushing test 2 —
2) Destructive tests
Hydraulic pressure cycling 3 — — —
Rolling bend cycling — 3 2 —
(optional, if requested by purchaser)
Hydraulic bursting test 4 5 — 3
Examination of a sectional cut — — 4 —
The hydraulic bursting test shall be carried out to qualify all DN hose assemblies.
When a hose assembly with a given DN and a given rated pressure, P , has been successfully sample
R
tested, any hose assembly of the same type, having:
— a rated pressure P ;
R
and
— a nominal diameter up to 1,25 DN
can be considered as approved except each DN hose assembly shall be hydraulic burst tested.
A hose assembly is said to be of the same type when the design and its characteristics are similar to the
tested hose; similarity is defined as having the same
— materials;
— welding method;
— type of corrugation (shape and method of manufacturing);
— method of joining (hose and end fitting);
— braid (type of braiding, i.e. calculated – according to diameters to obtain the same maximum tensile
stress in each wire, same materials, same welding method).
Bend radius and minimum hose length for sample hose assemblies are defined in Annexes B and C.
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oSIST prEN ISO 21012:2021
ISO/DIS 21012:2021(E)
Hose assemblies used for crushing test and destructive tests shall not be placed on the market.
5.2 Non-destructive tests and inspection
5.2.1 Documentation of materials
The materials, assembly methods, weld procedures and welder qualification for the manufacture of the
hose assemblies shall be identified and recorded.
5.2.2 Dimensional check
The outside diameter and total length of hose assemblies shall be measured, as delivered, to check
conformity with the drawings.
5.2.3 Cleanliness check
The hose assembly shall satisfy the requirements of EN ISO 23208:2019.
5.2.4 Pressure test
All flexible hose assemblies shall be subjected to a hydraulic pressure test, at room temperature (20 +/-
10) °C, equal to 1.5 x the rated pressure. The pressure shall be held for a minimum of 3 min. there shall
be no leaks. Under pressure, the overall length shall not increase by more than 3%.
Where austenitic stainless steel comes into contact with water, the chloride content of the water and
time of exposure shall be controlled so as to avoid stress corrosion cracking.
As an alternative to the hydraulic test, it is also permissible to perform a pneumatic test, at the same
pressure, provided that the necessary safety precautions are met (e.g. perform the test in a cage).
5.2.5 Leak test
The hose assembly shall be leak tested by immersion in water and pressurized with gaseous nitrogen
or air to the rated pressure.
The pressure shall be maintained for a minimum of 5 min. There shall be no leaks detected (i.e. no release
−4 3
of bubbles of gas in water). This corresponds approximately to a leak rate of less than 10 Pa m /s.
Table 2 — Conversion factors
3
Atm cm /s
3 3
Pa m /s Torr l/s or μ Hg l/s ft (STP)/h mbar l/s
3
Std cm /s
−4 −4 −4 −1 −4 −3
10 7,501 × 10 9,869 × 10 7,501 × 10 1,255 × 10 10
Other methods of equivalent or greater accuracy may be used for standard hose assemblies. Hose
assemblies specified for more stringent applications may have more stringent leak requirements (e.g.
helium leak testing under pressure).
5.2.6 Crushing test
This test is only carried out for hose assemblies made without corrugated stainless steel.
This test shall be performed on hose assemblies to simulate risks of damage when walking on a hose.
The hose assembly shall be held between two 200 mm × 200 mm rigid plates and a force of 1 000 N
shall be applied 10 times at the same location in the middle of each flexible hose.
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The hose assembly shall then be examined to check if there is any pronounced damage caused by this
test (a reduction in diameter greater than 20 % and appreciable damage to the braid is unacceptable).
After that, the destructive tests shall be carried out on these same hose assemblies.
5.3 Destructive tests
5.3.1 Hydraulic pressure cycling
This test shall be carried out on one hose assembly of the tested lot with pressure cycling from 1 bar to
rated pressure, at room temperature and at a frequency of <10 cycles per minute.
The test shall be stopped at 10 000 cycles and the hose assembly be subjected to a hydraulic burst test.
There shall be no leakage in the hose during the test.
5.3.2 Rolling bend cycling test
5.3.2.1 Corrugated metal hose assemblies
A rolling bend cycling test shall be carried out with the flexible hose assembly maintained at its rated
pressure, as described in Annex B.
The test hose assembly shall undergo 10 000 cycles without failure and then be subjected to a leak test
(leak rate higher than the one required in 5.2.5).
There shall be no leakage in the hose during the test.
5.3.2.2 Hose assemblies constructed from non-metallic materials or composites
A rolling bend cycling test shall be carried out (with the addition of some induced torque and
intermittent thermal shock) with the hose assembly maintained at its rated pressure as described in
Annex C.
The test hose assembly shall undergo 10 000 cycles.
5.3.3 Hydraulic bursting test
The tested samples shall be pressurized
...
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